Interleukin 7 stimulates growth of fetal thymic precursors of cytolytic cells: induction of effector function by interleukin 2 and inhibition by interleukin 4

Interleukin 7 (IL-7) and interleukin 2 (IL-2) stimulate the outgrowth of distinct populations of thymocytes in lobe submersion cultures (LSC) established with day 12-14 murine fetal thymus. Analysis of the expression of cell surface markers in previous studies showed that IL-7 favors the expansion of a more immature population. In the experiments reported here, populations grown in IL-7 and IL-2 were found to differ functionally as assessed by the expression of cytolytic activity. Whereas cells derived from IL-2-supplemented LSC were highly cytolytic for a broad panel of targets, cells that emerged in IL-7-supplemented cultures exhibited little or no such activity, even in the presence of facilitating lectin. However, there were cells with cytolytic potential present in IL-7-grown populations, as demonstrated by the abrupt appearance of effector function 3 days after their exposure to IL-2. Limiting dilution analysis showed that the absolute number of cells in the cytolytic lineage in fetal thymic lobes increased during culture in LSC. Interestingly, identical increases occurred in IL-7-supplemented and IL-2-supplemented LSC, despite the fact that only the latter population exhibited appreciable lytic activity. Collectively, these results suggest that IL-7 stimulates outgrowth of cell populations which contain functionally inactive cytolytic precursors whose activity is inducible by IL-2. In contrast to IL-2, IL-4 failed to stimulate the appearance of a lytic population from IL-7-supplemented LSC. Furthermore, IL-4 interfered with cell proliferation and acquisition of lytic activity normally induced by IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Regionally defective colonization of the terminal bowel by the precursors of enteric neurons in lethal spotted mutant mice

In order to gain insight into the process of colonization of the bowel by the neural crest-derived precursors of enteric neurons, the development of the enteric nervous system was examined in lethal spotted mutant mice, a strain in which a segment of bowel is congenitally aganglionic. In addition, nerve fibers within the ganglionic and aganglionic zones of the gut of adult mutant mice were investigated with respect to their content of acetylcholinesterase, immunoreactive substance P, vasoactive intestinal polypeptide and serotonin, and their ability to take up [³Hserotonin. In both the fetal gut of developing mutant mice and in the mature bowel of adult animals abnormalities were limited to the terminal 2 mm of colon. The enteric nervous system in the proximal alimentary tract was indistinguishable from that of control animals for all of the parameters examined. In the terminal bowel, the normal plexiform pattern of the innervation and ganglion cell bodies were replaced by a coarse reticulum of nerve fibers that stained for acetylcholineserase and were continuous with extrinsic nerves running between the colon and the pelvic plexus. These coarse nerve bundles contained greatly reduced numbers of fibers that displayed substance P- and vasoactive intestinal polypeptide-like immunoreactivity, but a serotonergic innervation was totally missing from the aganglionic bowel. During development, acetylcholineserase and uptake of [³Hserotonin appeared in neural elements in the foregut of mutant mice on the 12th day of embryonic life (E12), about the same time these markers appeared in the forgut in normal mice. By day E14, neurons expressing one or the other marker were recognizable as far distally as about 2 mm from the anus. The appearance of neurons in segments of gut grown for 2 weeks as expiants in culture was used as an assay for the presence of neuronal progenitor cells in the segments of fetal bowel at the time of explantation. Both acetyl- cholinesterase activity and uptake of [³Hserotonin developed in neuronsin vitro in expiants of proximal bowel between days E10 and E17. At all times, however, the terminal 2mm of mutant but not normal fetal gut gave rise to aneuronal cultures. In some mutant mice rare, small, ectopically-situated pelvic ganglia were found just outside aganglionic segments of fetal colon. Uptake of [³Hserotonin, normally a marker for intrinsic enteric neurites, was found in these ganglia.The experiments suppport the hypothesis that the terminal 2 mm of the gut in lethal spotted mutant mice is intrinsically abnormal and thus cannot be colonized by the precursors of enteric neurons. The defect seems to be specific in that both cells and processes of intrinsic enteric neurons, including all serotonergic and most peptidergic neurites, seem to be excluded from the abnormal region while extrinsic nerve fibers, including sympathetic and sensory axons, are able to enter the aganglionic zones. Since examination of neural progenitor cells has failed to reveal a significant proximo-distal displacement of these cells through the enteric tube during development of the murine bowel, a defect in the migration of precursor cells down the alimentary tract to the terminal gut seems unlikely to be substantially involved in the pathogenesis of aganglionosis. This conclusion is supported by the normal enteric nervous system in proximal regions of the mutant gut and the presence of enteric type neurons outside of, but at the same level as the aganglionic region.     

IL-8 as an important chemoattractant for neutrophils in ulcerative colitis and Crohn's disease.

IL-8 is generating increasing interest as a powerful neutrophil chemoattractant and activator. To elucidate the mechanisms of neutrophil infiltration in inflammatory bowel disease, we examined 33 patients with ulcerative colitis (UC), 18 with Crohn's disease (CD), eight with some other type of colitis, and 18 normal control subjects for measurement of IL-8 in homogenates of colonic biopsy specimens. The affected colonic mucosa was found to contain significantly more IL-8 in patients with active inflammatory bowel disease than in patients with inactive disease (UC, P < 0.001; CD, P < 0.001), in patients with other types of colitis (UC, P < 0.05; CD, P < 0.01), or in normal control subjects (UC, P < 0.001; CD, P < 0.001). Colonic IL-8 levels correlated significantly with the macroscopic grade of local inflammation, especially in patients with UC (P < 0.001). Colonic IL-8 levels also correlated well with the neutrophil numbers in mucosal tissue (UC, r = 0.950, P < 0.001; CD, r = 0.940, P < 0.001), and with colonic IL-1 beta (r = 0.911, P < 0.001) and tumour necrosis factor-alpha (TNF-alpha) levels (r = 0.604, P < 0.001) in patients with these two conditions. These data suggest a potential role for IL-8 and its regulatory cytokines IL-1 and TNF-alpha in mediating neutrophil infiltration of the gut wall in inflammatory bowel disease.     

Reciprocal heterotopic callosal connections between the two striate areas in Tupaia

Summary WGA-HRP injections were placed into area 17 close to the border with area 18 of Tupaia belangeri in order to study the callosal connections of the striate area in this animal. Most callosal neurons were found in the striate cortex (57.6–86.9%), some in the extrastriate area 18 (10.6–28.1%), and a few in even more temporal regions (2.5–14.3%). Concerning only the area 17, reciprocal homotopic connections could be observed as a strip along the area 17/18 border. Additionally, heterotopic callosal connections could be seen in regions representing the binocular visual field, especially the lower part. The area 17 cells were mostly located in the supragranular layers II and III (94.1–97.2%). But neurons could also be found in the infragranular layers, especially layer VI (2.6–5.2%) and in layer IV (0.2–1.1%). Homotopic projections were mostly seen in layers IIIc and V. The majority of the supragranular and infragranular neurons are pyramidal cells. However, a newly defined subpopulation of neurons, most probably stellate cells, were discovered forming a band in sublayer IIIc, very close to the layer III/IV border.     

Activation of the endothelium by IL-1 alpha and glucocorticoids results in major increase of complement C3 and factor B production and generation of C3a.

Constitutive secretion of complement C3 and factor B by the endothelial cell (EC) is lowered by therapeutic concentrations of glucocorticoids such as hydrocortisone or dexamethasone, whereas regulatory protein factor H production is increased by these hormones. In contrast, the proinflammatory cytokine IL-1 alpha has a stimulatory effect on C3 and factor B secretion by the endothelium and an inhibitory effect on factor H secretion. In this study, we examined the combined effect of IL-1 alpha and glucocorticoids on C3 and factor B expression by the endothelial cell. When dexamethasone or hydrocortisone were added to IL-1 alpha, significant potentialization of IL-1 alpha-induced stimulation of C3 and factor B production was observed, occurring at various concentrations of either stimuli. Dose-response experiments indicate that, in vitro, optimal concentrations are in the range of 10(-7) to 10(-5) M for dexamethasone and 50-200 U for IL-1 alpha. In contrast, dexamethasone counteracts, in an additive way, the inhibitory effect of IL-1 alpha on regulatory complement protein factor H production by EC. Such a potentialization between glucocorticoids and IL-1 alpha was not observed for another marker of endothelial activation, IL-1 alpha-induced stimulation of coagulation tissue factor expression. The association of glucocorticoids and IL-1 alpha therefore appears to be a specific and major stimulus for the secretion of complement C3 and factor B, two acute-phase proteins, by the endothelium. As a result of the in vitro endothelium stimulation by glucocorticoids and IL-1 alpha, C3a is generated in the vicinity of the endothelial cell. This study further suggests that complement activation, with its deleterious consequences, may result from the stimulation of endothelium in situations where high levels of IL-1 alpha and endogenous glucocorticoids coexist, such as in septic shock.     

In vivo effects of cytokines on psoriatic skin grafted on nude mice: involvement of the tumour necrosis factor (TNF) receptor

Following engraftment of human involved psoriatic skin to nude mice there is a partial normalization of pathology associated with a loss of inflammatory leucocytes. However, the epidermis remains hyperproliferative, which may reflect a primary defect. The roles of TNF-α, IL-1 and IL-6 in epidermal hyperproliferation of grafted psoriatic lesions were investigated. Before and after treatment, grafts were analysed to determine epidermal thickness and labelling index (LI). HLA-DR, intercellular adhesion molecule-1 (ICAM-1), and TNF receptor (TNF-R; p75 and p55) expression were determined by immunoperoxidase staining. Psoriatic epidermis was found consistently to be negative for p55 TNF-R and p75 TNF-R before grafting. Following engraftment, TNF-R-positive cells (i.e. p55 by keratinocytes; p75 by epidermal dendritic cells) were identified throughout the epidermis. Higher numbers of p75 TNF-R epidermal dendritic cells were found in grafts following a course of TNF-α, IL-6 or IL-1 treatment. The p55 form of the TNF-R expressed by keratinocytes was significantly elevated after treatment with TNF-α or IL-6. HLA-DR and ICAM-1 were also expressed in these grafts. TNF-α, anti-IL-1, and anti-IL-6 treatment induced a marked decrease in the epidermal thickness and LI of psoriatic graft tissue, correcting the hyperproliferation associated with psoriatic epidermis. Supraphysiological levels of TNF-α may saturate and consequently down-regulate their own receptors, leading to a paradoxical inhibitory effect.     

IL-18在体外培养系统中诱导肿瘤快速杀伤效应及肿瘤特异性CTL

目的应用rhlL-18在体外培养系统(Coculture system in vitro，CCs)中诱导快速肿瘤杀伤效应及诱导肿瘤特异性细胞毒性T淋巴细胞(Cytotoxic T Lymphocyte，CTL)。方法 采用StemSep^TM免疫磁性细胞分离法分离人外周血NK细胞、T细胞及树突细胞(DCs)，流式细胞仪分析细胞表型，125I-UdR标记的细胞毒实验检测杀伤活性，ELISA方法检测IFN-7的产生量。结果 在CCs中，rhIL-18诱导出快速肿瘤杀伤效应，这种杀伤效应无抗原特异性、不受MHC限制，DCs和T细胞的存在与否对其无明显影响。在同一培养系统中，肿瘤抗原存在的条件下，96h后，rhIL-18能够诱导并促进CTL介导的肿瘤特异性杀伤效应。结论 rhIL-18能够在体外培养系统中相继诱导肿瘤快速杀伤效应及肿瘤特异性CTL。     

IL—2／LAK细胞对麻风杆菌感染巨噬细胞的溶解作用

观察了小鼠IL-2/LAK细胞体外对麻风杆菌感染巨噬细胞(Mφ)的溶解作用。结果显示,当麻风杆菌感染Mφ比率在1:1,10:1和50:1时,经体外培养1,3和5天后,效应细胞与靶细胞比例在10:1时,对麻风杆菌感染Mφ比率在10:1和50:1的靶细胞溶解作用比没有感染的Mφ或麻风杆菌与Mφ比率1:1的靶细胞显著增加。而且溶解百分率随着培养时间增加而提高。用放射性同位素标记麻风杆菌的代谢活力测定发现,LAK细胞能抑制麻风杆菌氧化(14)~C-棕榈酸产生(14)~CO_2。提示IL-2/LAK细胞在溶解麻风杆菌感染的巨噬细胞时,可能还具有影响胞内杀菌物质对麻风杆菌活力代谢的作用。     

Anti-proliferative effects of phosphodiester oligodeoxynucleotides

The immunostimulatory effects of cytosine-phosphate-guanosine (CpG)-containing oligodeoxynucleotides (ODNs) have been extensively documented. In this paper, we describe the inhibitory effects of ODNs that contain natural phosphodiester backbones (O-ODNs) on the immunostimulation caused by CpG-containing phosphorothioated ODNs (CpG-S). CpG-S stimulation of mouse splenocyte proliferation was reduced by the addition of O-ODNs that contained or lacked the CpG-motif (CpG-containing phosphodiester oligodeoxynucleotide, CpG-O or GpC-O). The total number of cultured splenocytes was up-regulated by CpG-S, whereas repetitive addition of O-ODNs to the cell cultures inhibited this effect. The frequency of T2-like B cells was found to be increased by CpG-S. The culture supernatants of CpG-S-treated splenocytes contained elevated levels of IL-10 and IL-6. However, IL-10 and IL-6 production was down-regulated significantly by the combination of CpG-S and either CpG-O or GpC-O. The O-ODN mediated inhibition of proliferation was less pronounced in IL-10-/- mice. Thus, the O-ODNs, irrespective of CpG content, exerted inhibitory activities on the proliferation of B cells. These anti-proliferative effects appear to be mediated both by the down-regulation of IL-10 production and increased apoptosis.